Introduction and objective: This study aims to clarify if the GnRH agonist STOP-antagonist protocol versus the GnRH antagonist protocol can be useful in improving IVF (In vitro fertilization) outcomes in patients with poor ovarian response candidates for IVF. Methods: The present study was conducted as a single-blind clinical trial in the infertility ward of Arash Hospital of Tehran University of Medical Sciences. In this study, 133 patients with a poor ovarian response (POR) according to Bologna criteria were randomly assigned to two groups GnRH agonist stop-antagonist protocol and GnRH antagonist protocol. The number of dominant follicles and number of oocytes retrieved, the number of embryos and their grade, level of antagonist used, level of gonadotropin used, length of days of stimulation and endometrial thickness, level of estrogen, level of progesterone, trigger day, and fertilization rate were measured. Results: In the present study, the frequency of dominant follicles in the GnRH agonist stop-antagonist group was significantly higher than that in the GnRH antagonist group (p-value = 0.01). The number of embryos in the GnRH agonist stop antagonist group was significantly higher than that in the GnRH antagonist group (p-value = 0.02). The percentage of AB embryo agonists in the GnRH agonist stop _anta group was significantly higher than that in the GnRH antagonist group (p-value = 0.003). The number of mature oocytes in the GnRH agonist stop _antagonist group was more than that in the GnRH antagonist group, but the difference between the two groups was not statistically significant. The number of used gonadotropin doses in the GnRH agonist stop _antagonist group was significantly higher than that in the GnRH antagonist group (p-value = 0.01). The number of used antagonists in the GnRH antagonist group was significantly higher than that in the GnRH agonist stop _antagonist group (p-value = 0.02). Conclusion: The GnRH agonist stop-Anta protocol is a valuable tool for the treatment of poor ovarian responders. However, controlled prospective randomized studies with larger sample sizes are needed.